The invention relates generally to an electrooptical device and more particularly to a nematic multi-colored liquid crystal display that does not require the use of color filters to vary the color of the display.
As described in Japanese Patent Laid-Open No. 50511/1985, certain liquid crystal displays include supertwisted nematic liquid crystal material in which the twist angle of the liquid crystalline molecules exceeds 180.degree.. The product of the optical anisotropy n and the thickness d of the liquid crystal layer is 0.7 to 1.1 .mu.m. This liquid crystal display (LCD) is colored because double refraction birefringence occurs when it is driven by a dynamic drive. A non-selecting voltage turns the display yellow and a selecting voltage turns the display blue. Intermediate voltages turn the color of the LCD from yellow to blue through a somewhat blue-green intermediate color stage as shown in the CIE chromaticity diagram of FIG. 18. The LCD cannot exhibit many other colors outside of this range. Accordingly, one cannot obtain a sufficiently large variety of colors by applying intermediate voltages and selecting and non-selecting voltages.
Other color LCD devices include color filters to display multiple colors. These devices typically include sets of three pixels covered with filters of the additive primary color: red, green and blue. However, providing pixel sized color filters over individual LCD displays involves intricate manufacturing techniques and can be costly and complex.
Accordingly, it is desirable to provide a full color electrooptical device which overcomes the shortcomings of the prior art.